Venus Flytraps Catch Their Prey By Counting

A 2015 study has found that Venus flytraps recognize, ensnare, and digest their prey by "counting" the number of times the insect brushes against its sensory hairs. A fly that brushes its leg against the plant's hair only once could live another day. But a second brush is crucial: it prompts the flytrap to send water into its leaves, which can snap shut over the fly in a tenth of a second. As the trapped insect continues to struggle against the hairs, the plant continues to receive electrical impulses from the contact. The fifth impulse is the next important one, and it prompts the fly trap to produce digestive enzymes.